4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Arnd Bergmann <arnd@xxxxxxxx>
commit cff52e5fc4cfc978b7df898dc14a0492c7ef0ae8 upstream.
gcc warns about the timestamp in drm_wait_vblank being possibly
used without an initialization:
drivers/gpu/drm/drm_irq.c: In function 'drm_crtc_send_vblank_event':
drivers/gpu/drm/drm_irq.c:992:24: error: 'now.tv_usec' may be used uninitialized in this function [-Werror=maybe-uninitialized]
drivers/gpu/drm/drm_irq.c:1069:17: note: 'now.tv_usec' was declared here
drivers/gpu/drm/drm_irq.c:991:23: error: 'now.tv_sec' may be used uninitialized in this function [-Werror=maybe-uninitialized]
This can happen if drm_vblank_count_and_time() returns 0 in its
error path. To sanitize the error case, I'm changing that function
to return a zero timestamp when it fails.
Fixes: e6ae8687a87b ("drm: idiot-proof vblank")
Reviewed-by: David Herrmann <dh.herrmann@xxxxxxxxx>
Cc: Rob Clark <robdclark@xxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Reviewed-by: Mario Kleiner <mario.kleiner.de@xxxxxxxxx>
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
Link: http://patchwork.freedesktop.org/patch/msgid/20161017221355.1861551-6-arnd@xxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/drm_irq.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -952,8 +952,10 @@ static u32 drm_vblank_count_and_time(str
u32 vblank_count;
unsigned int seq;
- if (WARN_ON(pipe >= dev->num_crtcs))
+ if (WARN_ON(pipe >= dev->num_crtcs)) {
+ *vblanktime = (struct timeval) { 0 };
return 0;
+ }
do {
seq = read_seqbegin(&vblank->seqlock);
--
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